Process of reacting an isocyanate with an active hydrogen compound in the presence of an antimonite catalyst



United States Patent 3,245,957 PROCESS OF REACTING AN ISOCYANATE WITH ANACTIVE HYDROGEN COMPOUND IN THE PRESENCE OF AN ANTIMONITE CATALYSTRaymond R. Hindersinn, Lewiston, N.Y., and Stephen M. Creighton,Edmonton, Alberta, Canada, assignors to Hooker Chemical Corporation,Niagara Falls, N.Y., a corporation of New York No Drawing. Filed Aug.18, 1964, Ser. No. 390,445

7 Claims. (Cl. 260-75) This invention relates to the catalysis of thereaction between isocyanates and compounds containing one or.

more active hydrogen atoms by certain antimony compounds.

This application is a continuation-in-part of copending applicationSerial Number 803,820, filed April 3, 1959, now abandoned.

Organic amines are conventionally used as catalysts for the reactionbetween isocyanates and active hydrogencontaining compounds. Primary andsecondary amines are relatively poor catalysts because they react withthe isocyanates, thereby causing a removal of the primary and secondaryamine from the system. Although tertiary amines are not reactive withisocyanates when residual amines are allowed to remain in the system,they tend to promote hydrolysis of the resulting compositions. Inaddition to this, residual amines release objectionable odors.Furthermore, to obtain very fast reactions in some systems, largeamounts of these amines are required to adequately catalyze thereaction.

Accordingly, an object of the invention is to provide.

catalysts for the reaction between isocyanates and activehydrogen-containing compounds, whichcatalysts-are generally unreactivewith isocyanates under the conditions of the reaction; do not tend topromote significant hydrolysis.

of the resulting compositions; and do not release objectionable odors.Another object of the invention is to provide catalysts for the reactionbetween isocyanates and compounds which contain one or more activehydrogen atoms in the process wherein the catalyst can be used in smallquantities and still exhibit substantial catalytic effect. Furtherobjects of the present invention will be apparent from the followingdetailed specification.

In accordance with the invention, We have found that antimonyalcoholates catalyze the reaction between a compound containing theradical N=C=O and an active hydrogen-containing compound. The metalliccompounds of the invention have many advantages over the compoundsutilized by' the prior art to catalyze the reaction between isocyanatesand compounds which contain one or more active hydrogen atoms. Thesecompounds frequently exhibit greater catalytic activity than thecompounds normally used by the prior art. This advantage enables greatercontrol over the reaction and allows the use of very small quantities ofcatalyst to obtain substantial catalytic effect. In addition, most ofthemetallic compounds of the present invention are unreactive withisocyanates under the conditions of the reaction.

Furthermore, because of the neutral character of most of'the metalliccompounds of the invention, they do not contribute significantly to thehydrolytic instability'of the resulting compositions. The metalliccompounds of the present inventiondo not'release objectionable odors, asdo many of the catalytic compounds of the prior art.

They are generally soluble in the reaction medium at ambienttemperatures.

The antimony compounds encompassed by the invention include boththetrivalent and pentavalent antimony alcoholates. Illustrative ofclasses of compounds con-- atoms are preferably chlorine, bromine andmixtures thereof.

Exemplificative of specific compounds contemplated are the following:tris (Z-chloroethyl) antimonite, tris (2- chloropropyl) antimonite, tris(2-chlorobutyl) antimonite, tris (2-chloro-2-phenylethyl) antimonite,tris (2-ethylh'exyl) antimonite, tris (n-octyl) antimonite, tn'benzylantimonite, triphenyl antimonite, tris (Lchloroethoxy), antimonydibromide, tris (Z-chloropropoxy) antimony dibromide, tris(2,3-dichloropropoxy) antimony dibromide, tris (2-chloropropoxy)antimony dichloride, tris (2,3-dichloropropoxy) antimony dichloride,tris (2- chloro-butyoxy) antimony dichlororide, tris (2-ethylhexoxy)antimony dibromide, tris (n-octoxy) antimony dibromide, tribenzoxyantimony dibromide and tris (2- chloro-Z-phenylethoxy) antimonydibromide. In addition, mixtures of the catalysts of the invention canbe used.

The compounds prepared by the process of the present invention, i.e.,the raction products of an isocyanateand an active hydrogen-containingcompound, find utility in many applications. For example, they areuseful in the preparation of polyurethane foams, coatings, adhesives,chemical intermediates and the like. 1

The metallic compounds of the present invention exhibit greatercatalytic activity than the catalysts of the prior art. In thepreparation of polyurethane foams, for example, the metallic compoundsof the present invention have significantly greater catalytic activitythan N-methyl morpholine (a standard catalyst for this purpose), basedon equal molar quantities of nitrogen and metal.

Active hydrogen-containing compounds vary in their reactivity withisocyanates. The amount of catalyst used will, of necessity, vary withthe reactivity of the active hydrogen-containing compound. Normally, theI metallic compounds of the present invention are employed in an amountfrom about 0.01 to about 1 weight percent based on the Weight ofreactants to adequately catalyze the reaction between an isocyanate andan alcohol-containing compound, noting, of course, that the morecatalyst employed, the greater the catalytic effect. In the reactionbetween an isocyanate and an alcohol-containing compound, if greaterthan 0.5 percent by weight of the metallic compounds of the presentinvention are .used in a batch system, the catalytic elfect is normallytoo great to allow for convenient handling; in a continuous type systemwhere extra-ordinary catalytic effect is required or can be tolerated,greater than 0.5 percent can be used.

The compositions catalyzed by the present invention are the reactionproducts of organic isocyanates and active hydrogen-containingcompounds. Any monoisocyanate or polyisocyanate can be employed, i.e.,any organic compound which contains the radical N=@O.

Patented Apr. 12, 1966 diisocyanate, 1,3-cyclopentylenediisocyanate,-1,2-cychexylene diisocyanate, 1,4-cyclohexylenediisocyanate, cyclopentylidene diisocyanate, cyclohexylidenediisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, 4,4-diphenyl propanediisocyanate, 4,4'-diphenyl methane diisocyanate,l-methyl-2,4-phenylene diisocyanate, 4,4- diphenylene diisocyanate,1,2-pro'pylene diisocyanate, 1,2- butylene diisocyanate, 2,3-butylenediisocyanate, 1,3-butylene diisocyanate, ethylidene diisocyanate,propylidene diisocyanate; butylene diisocyanate'; 1,3,5-benzenetriisocyanate; 2,4,6-monochlorobenzene triisocyanate; 4,4,4"-

triphenylmethane triisocyanate; 2,4,4'-diphenyl triisocy-.

anate; polymethylene polyphenylisocyanate; the liquid reaction productsof (1) diisocyanates and (2) polyols or polyamines; and the like. Inaddition, isothiocyanates and'rnixtures of isocyanates can be employed.Also contemplated are the many impure or crude polyisocyanates that arecommercially available such as crude mixtures of methylenebis(4-phenylisocyanate) The term active hydrogen atom refers tohydrogens which display activity according to the well-knownZerewitinoif test as described by Kohler in Journal of the AmericanChemical Society, 49, 3181 (1927). Such active hydrogen-containingcompounds are any organic compounds containing one or more activegroups. Typical compounds contemplated include the following classes ofcompounds: alcohols; phenols; thiols; amines;

amides; canboxylic acids; etc., as well as compounds containing mixturesof the above groups. Illustrative compounds include: ethyl .alcohol,methyl alcohol; ethylene glycol, diethylene glycol; hexamethyleneglycol; decamethylene glycol; glycerol; 1,2,6-hexanetriol; resorcinol;

hydroquinone; cyclohexanol; 1,2-ethanediol; decamethylene dithiol;thioresorcinol; ethylamine; ethanolamine; diethanolamine;triethanolamine; N-ethylethanolamine; m-

phenylenediamine; 'propylenediamine; ethylenediamine;

2,4-tolylenediamine; bis(4-aminophenyl) methane; parninophenol;hexamethylene diamine; adipamide; 4- aminobenzamide;1,4-cyclohexanedisulfonamide; 1,3-propanedisulfonamide; succinamide;1,4-butanedisulfonamide; benzoic acid; acetic acid; citric acid;polyvinyl mercaptan; phthalic acid; adipic acid; and the like.

Generally preferred as the active hydrogen-containing compound are thehydroxyl-containing polymers having a hydroxyl number of about 25 to900, such as the alkyd resins which are the reaction product of apolyhydric alcohol and a polycarboxylic compound. These alkyd resins aregenerally preferred in the present invention. The alkyd resins can bereacted with an isocyanate in the presence of a catalyst of the presentinvention and also in the presence of a foaming agent, to give apolyurethane foam For example, a useful polyurethane mixtures thereof.The carboxylic compounds, can be aliphatic, cyclo aliphatic, aromatic,or heterocyclic and either saturated or unsaturated. Among thepolycarboxylic compounds which can be used to form the polyester are:rnaleic acid; fumaric acid; phthalic acid; isophthalic acid;terephthalic acid; tetrachlorophthalic acid, aliphatic acids such asoxalic, malonic, succinic, glutaric and adipic;1,4-cyclohexadiene-l,2-dicarboxylic acid and the like. Additionalpolycarboxylic compounds which can be used to form the polyester areDiels-Alder adducts of hexahalocyclopentadiene and a polycarboxyliccompound, wherein the halogen is selected from the group consisting ofchlorine, bromine, fluorine and mixtures thereof, for example:l,4,5,6,7,7-hexachlorobicyclo- (2.2.1)-5-heptene-2,3-dicarboxylic acid;l,4,5 ,6-tetrachloro-7-7-difluorobicyclo- 2.2. l -5-heptene-2,3dicarboxylic I acid; l,4,5,6,7,7-hexabromobicyclo-(2.2.1)-5-heptene-2,3-

dicarboxylic acid; 1,4,5,6-tetrabromo-7,7-difiuorobicyclo-(2.2.1.)-5-heptene-2,3-dicanboxylic acid; and the like. Mixtures of anyof the above polycarboxylic compounds can be employed.

structure is desired, the whole alcohol component may be made up of atrifunctional alcohol such as glycerol.

Where a less rigid final product is desired, a difunctional polyhydricalcohol such as ethylene glycol or 1,4-butanediol may be utilized asthat part of thepolyhydric alcohol component. Other glycols such asdiethylene-glycol, tri-' ethylene glycol, propylene glycol, dipropyleneglycol,

other polypropylene glycols, butylene glycols, polybutylene glycols, andthe like can also be used Among the polyhydric alcohols which can beused are glycerol, hexanetriol, butanetriol, trimethylol propane,trimethylol ethane, pentaerythritol, mannitol, sorbitol,cyclohexanediol-1,4 glycerol monoethyl ether and the like.

Polyphenolic compounds which can be employed in producingthepolyethersare the reaction products of phenolic compounds withaldehydes, such as phenol-formaldehyde novolac resins.

Examples of monomeric 1,2-epoxides used in preparing the polyethersinclude ethylene oxide, propylene oxide, butylene oxide, isobutyleneoxide, 2,3-epoxyhexane, 3- ethyl-2,3-epoxyoctane, epichlorohydrin,epibromohydrin, styrene oxide, glycidyl ether, methyl glycidyl ether,phenyl glycidyl ether, butyl glycidyl sulfide, glycidylmet-hyl sulfone,glycidyl rnethacrylate, glycidyl acrylate, glycidyl benzoate, glycidylacetate, glycidyl octanoate, glycidyl sonbate, glycidyl allyl phthalateand the like.

Any foaming agent commonly used in the art can be employed. Foamingagents in this art are generally those materials that are capable ofliberating gaseous products when heated, or when reacted with anisocyanate. Preferably foaming is accomplished by introducing a lowboiling liquid into the catalyzed resin. The heat of reaction'is thensufiicient to expand the mixture to a foam stable enough to retain itsshape until the resin gels.

Suitable liquids are the fiuorochlorocar'bons boiling in the foam ofdesirable properties can be easily prepared from an alkyd resincontaining an excess of hydroxyl groups.

Also contemplated as the active hydrogen-containing compound of theinvention are the polyethers,which are the reaction products of.(lleither'a polyhydric, alcohol,

a polycarboxylic acid or a olyphenolic compound, and

rangeof .30 to 50 degrees centigrade, and the mixtures thereof, forexample, trichlorofluoromethane, trichlorotrifluoroethane,dichloromonofiuoromethane, monochloroethane, monochloromonofluoroethane,difiuoromonochloroethane, and difiuorodichloroethane.

Another foaming system that is suitable for carrying out the foamingreaction at an elevated, temperature. is found in Unites States Patent2,865,869, which discloses and claims the use of tertiary alcohols inthe presence of strong, concentrated acid catalysts. Examples oftertiary alcohols include: tertiary amyl alcohol; tertiary butylalcohol; 2-methyl-3-butyn-2-ol; l-methyl-l-phenylethanol;

and 1,1,2,2-tetnapheny'lethanol, etc. Examples of catalysts include:sulfuric acid; phosphoric acid; sulfonic acid;

p This is desired to provide a'meansv for branching the polyester. Wherean even more rigid and aluminum chloride; etc. In addition, varioussecondary alcohols and glycols may be used as: l-phenyl- 1,2-ethanediol;2-butanol; etc. Generally, secondary alcohols should be used with strongconcentrated acid catalysts as above; however, certain secondaryalcohols may be used without the acid catalyst, e.-g., acetaldol,chloral hydrate, etc. Other foaming agents that may be used include thefollowing: polycarboxylic acids, polycarboxyl-ic acid anhydrides,dimethylol ureas, polymethylol phenols, formic acid and tetrahydroxymethylphosphonium chloride. In addition, mixtures of the above foamingagents can be employed.

In preparing the polyurethane compositions of this invention, thehydroxyl containing polymer, either alkyd resin or polyether, andpolyisocyanate are preferably reacted in a ratio sufficient to provideabout eighty-five to one hundred and fifteen percent of isocyanategroups with respect to the total number of hydroxyl and carboxyl groupspresent in the hydroxyl containing polymeric material (and the foamingagent, if one is provided). The reaction temperature igenerally rangesfrom about twenty to about one hundred and twenty degrees centigrade,although higher and lower temperatures can be used.

The following is an exemplificative discussion of the preparation ofsuch an alkyd resin, wherein, for illustrative purposes, the alkyd resinwas prepared from a mixture of polyesters. The first of the polyesterswas prepared from a mixture of four moles of 1,4,5,6,7,7-hexachlorobicyclo-(2.2.1)-5-heptene 2,3 dicarboxylic acid, two moles ofadipic acid, and 7.6 moles of glycerol, and cooking the mixture to anacid number of from about five to about six. The other polyester wasprepared in a similar manner from a mixture of six holes of adipic acidand ten moles of trimethylol propane, and cooking the mixture to an acidnumber of from about zero to about one. The polyester mixture was thenprepared by admixing equal parts of the above polyesters and, inaddition, about ten percent by weight of tricresyl phosphate was added.One hundred sixty-five parts by weight of this alkyd mixture werereacted with three hundred and one parts by weight of a semi-prepolymer(formed by the reaction of twenty-five parts of chlorine-containingpolyester iand seventy-five parts of tolylene diisocyanate) in thepresence of a oataylst of the present invention, for example, 2.0 partsby weight of tris(2-chloroethyl) antimonite, and ten parts by weight ofwater. The components were then rapidly mixed and allowed to expand andcure into a polyurethane foam.

A test has been used to evaluate the relative merits of the catalysts ofthe present invention. The following procedure was used. Fivemilliliters of cyclohexanol were added to a volumetric flask containing6.7 millimoles of the catalyst, and the solution raised to a volume of25 milliliters by the addition of anhydrous toluene. Phenyl isocyanate(11.91 grams) was added to a 100 milliliters volumetric flask anddiluted to 100 milliliters with toluene. One hundred milliliters of adi-n-butylamine solution in toluene was similarly prepared from 13.8grams of di-n-butylamine. The test was performed in a 125 millilitersstoppered Erlenmeyer flask by adding milliliters of the isocyanatesolution from a pipet, followed by 5 milliliters of the catalystsolution in cyclohexanol. The mixture was stirred continually during theaddition. Exactly 3 minutes after the addition of the cyclohexanolsolution, an excess of dibutylamine solution (10 milliliters) 'was addedto quench the reaction and the mixture allowed to stir for fifteenminutes, and S0 milliliters of isopropyl alcohol added. The excess amineremaining was titrated with standard hydrochloric acid in the presenceof .bromophenol blue or bromocresol green indicator. The amount ofisocyanate reacted with the alcohol was then calculated by standardmethods. According to this test, a known quantity of cyclohexanol wasadded to a flask containing a known quantity of anhydrous toluene,followed by weight amounts of isocyanate and the catalyst to be tested.The reaction was allowed to proceed at room temperature for exactlythree minutes in order to react only a part of the isocyanate available,whereupon an excess of di-n-butylamine was added to quench :thereaction. If no catalyst is used, the amount of isocyanate unreacted inthe mixture at the end of three minutes is known, i.e., one hundredweight percent of isocyanate groups are unreacted. If all of theisocyanate were allowed to react, no information could be obtained whenthe cataylst is added. But, if the reaction is not allowed to go tocompletion, the effect of the catalyst on the rate of the reaction canbe determined analytically.

A blank was run without the isocyanate with all determinations. Thisshows the effect of the catalyst on the alcohol in order to determinethe correction factor for any reaction of alcohol and catalyst. This isespecially important in the case of the chlorinated-type metalliccompounds of the present invention. In addition to this, the othercorrection factors apparent to those skilled in the art were applied.

In the following table, the diiference in catalytic effect isexemplified using 0.0134 equivalent of active nitrogen or metal in everycase.

Percent by Example Catalyst Weight of N=C=O Unreacted 1 None 100. 0 2Iris(2-chloroethyl) antimonite 10.9 3 'Iris(2-chloropropyl) antimonit6.8 4.-" Tris(n-octyl) antimonite 6.0 5 Triethylamine 78. 7 6 N-methylmorpholine 83.5

This invention can be embodied in other forms or carried out in otherways without departing from the spirit or essential characteristicsthereof. The present embodiment is, therefore, to be considered as intall respects illustrative and not restrictive.

What is claimed is:

1. The process which comprises reacting together an organic compoundcontaining the radical N C=O, and an active hydrogen-containing compoundas determined by the Zerewitinolf method, said reaction being performedin the presence of a catalytic amount of a compound selected from thegroup consisting of a tris (hydrocarbyl) antimonite and a tris(halohydrocarbyl) antimonite, wherein the 'hydrocarbyl radicals have 1to 8 carbon atoms and the halogen substituents are selected from thegroup consisting of chlorine, bromine and mixtures thereof.

2. The process which comprises reacting together an organic compoundcontaining the radical -N:C:O, and an active hydrogen-containingcompound as determined by the Zerewitinolf method, said reaction beingperformed in the presence of about 0.01 to about 1.0 weight percent oftris (2-chloroethyl) ant-imonite based on the weight of reactants.

3. The process which comprises reacting together an organic compoundcontaining the radical -N=C=O, and an active hydrogen-containingcompound as determined by the Zerewitinotf method, said reaction beingperformed in the presence of about 0.01 to about 1.0 weight percent oftris (2-chloropropyl) antlmonite based on the weight of reactants.

4. The process which comprises reacting together an organic compoundcontaining the radical N C=O, and an active hydrogen-containing compoundas determined by the Zerewitinoff method, said reaction being performedin the presence of about 0.01 to about 1.0 weight percent of tris(n-octyl) antimon-ite based on the weight of reactant-s.

5. The process which comprises reacting together an organicpolyisocyanate, and a hydroxyl-containing polymer having a hydroxylnumber of about 25 to 900, said reaction being performed in the presenceof a catalytic amount of a compound selected from the group consistingof a tris (hydrocarbyl) antimonite and a tris (halohydrocarbyl)antimonite, wherein the hydrocarbyl radicals have 1 to 8 carbon atomsand the halogen substituents are selected from the group consisting ofchlorine, bromine and mixtures thereof.

6. The :process of claim 5 wherein the hydroXyl-containing polymer is analkyd resin comprising the reaction product of a polyhydric alcohol anda polycarboxylic compound.

, s .v 4 7 The process of claim 6 wherein the polycarboxylic compound is'1,4,5, 6,7,7 hexachlorobicyolo-(ZZ.1)-5- heptene- 2,3 dicarboxylicacid.V, a r 1 References Cited by the Examiner UNITED STATES PATENTS LEON J.BERCOVITZ, Primary Examiner.

DONALD E. CZAJA, Examiner.

1. THE PROCESS WHICH COMPRISES REACTING TOGETHER AN ORGANIC COMPOUND CONTAINING THE RADICAL - N=C=O, AND AN ACTIVE HYDROGEN-CONTAINING COMPOUND AS DETERMINED BY THE ZEREWITINOFF METHOD, SAID REACTION BEING PERFORMED IN THE PRESENCE OF A CATALYTIC AMOUNT OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF A TRIS(HYDROCARBYL) ANTIMONITE AND A TRIS (HALOHYDROCARBYL) ANTIMONITE, WHEREIN THE HYDROCARBYL RADICALS HAVE 1 TO 8 CARBON ATOMS AND THE HALOGEN SUBSTITUENTS ARE SELECTED FROM THE GROUP CONSISTING OF CHLORINE, BROMINE AND MIXTURES THEREOF. 